A strike at postal sorting offices will delay deliveries in parts of the country on Friday, and the dispute is set to widen next week.

National mail company Posti says that due to unofficial walkouts by workers in Tampere, Vantaa and Jyväskylä, there may be some delays to package deliveries in those areas.

The postal workers’ union PAU has called for strikes starting on Sunday at 10pm and with workers expected to return to work on 5 September, but some workers walked out on Thursday and Friday on hearing the news that their pay was to be cut from November.

The dispute stems from a move by Posti to transfer some 700 workers from the current sector-wide collective agreement to an agreement covering newspaper deliveries with significantly worse terms and conditions. The change will effectively cut workers' pay while introducing bonuses for productivity, customer satisfaction and quality of work.

PAU claims that the move would see pay cuts of up to 50 percent, with the average affected worker losing 30 percent of their salary.

The 700 affected workers deal with package and online shopping deliveries, and their new terms and conditions are slated to come into force from 1 November.

Posti said yesterday in a statement that the move is part of an efficiency drive that is targeting 150-200 million euros in annual savings by 2021.